The inability to maintain or play to a rhythm.
To have an Awful Sense of rhythm.
Origins: This term is based on two stereotypes at once, African americans have a good sense of rhythm and Caucasian people do not.
Usage: It is most commonly used when referring to an African american with said inability, but may be used when referring to a Caucasian. But as prevailing stereotypes indicate more often than not this would be redundant, unless referring to a well known Caucasian musician or any musician, who's music has taken a recent decline.
Antonym for Rhythmatic